I'm not exactly sure what you're asking, but if you want to use B use:
IF BUTTON() AND #B THEN (Whatever you want)
If you want it to do what you just asked, just use 12Me23's method.
REPEAT:UNTIL BUTTON() AND #A
CLS 'or ACLS
? "Hello"
REPEAT:UNTIL BUTTON() AND #B
0そうだね プレイ済み